My Z-Drive Mini (and some extra build info)

[MixGtrz]

This is a bit of a long post, but hopefully it will prove to be helpful to others that want to do this build.

Firstly, the pedal sounds GREAT! I used to have a “68 Pedals” clone (Hong Kong) of this and I have always regretted selling it. Now I have my own!

I will get into the sound and what I changed a bit later, but one thing I would like to point out straight away is some differing information in part of the “Z-Drive Mini” Build Document. (well… I missed it at first)

The drawings on page 2 of 3 that show the control pots wiring, show both versions of the PCB (pre and post 2020). The pre-2020 PCB  (which is the one specifically showing the pots & wiring) have the pot leg numbers 1-3  from left to right. The post-2020 PCB is actually laid out with pot leg numbers 3-1 from left to right.

I should have picked this up before I soldered the wiring, but alas, I did not. So as a result, the pots operated in reverse when I plugged it in and tested. Easy fix. No harm, no foul.

Now, the next thing I discovered in testing was that the VOICE control actually *needs* to be reverse if you want it to work like the original “Z”.
It should be a C10k pot (reverse taper) or since it’s linear, just wire it “backwards” like I did.

Now it works so that turning anti-clockwise will increase the bottom-end response, and turning clockwise will reduce the bottom-end response.

The final thing I want to share is about the op-amp. The kit comes with TL-072 which is pretty standard with heaps of our fave OD’s and Distortions, and sounds great, but I’ve read threads in other forums regarding various BYO Z-style pedals, of using an LM-1458 instead.

I had an LM-1458 and tried it. I did A/B tests between the two chips and the 1458 won out for me as well. The TL-072 doesn’t sound bad at all, but definitely different.
The 1458 is a little less gain (still plenty IMO) but has a much more obvious transparency.

I know tone is a super subjective thing, and lies in the “ears of the beholder”, but I would encourage anyone with this pedal or thinking about building one, try a 1458 and see what you think. That’s the beauty of these things… you can do what you want!

Thanks for reading.

Cheers,
Mick

[brd]

I ran out to my shop and grabbed my box of IC’s and my notes to see if I had any LM-1458’s, but sadly I have none in stock here.

Swapping IC’s is a very easy mod, I highly recommend trying it. The hardest part is not bending the legs prying them out of a socket. ( no I don’t have the tool )

I used all OPA-2134’s in my last Mule Kicker build, IMO the best sounding Klon I’ve built yet.

Have a look at this link http://www.geofex.com/article_folders/potsecrets/potscret.htm ,  I hope Barry doesn’t mind me posting that here. It’s a lot of information, but the section on pot tapers is helpful and also describes how to make your own custom tapers if you ever need that.

I think Bruce Lee once said “whatever works use it”. ( or something like that). So yeah, that’s the beauty of it, we can make them any way we want.

Best

BRD

[MixGtrz]

Thanks BRD.
I guess swapping chips is technically a mod, but it almost doesn’t feel like it because it’s so easy to do (providing they’re socketed).
I don’t have any problem removing/replacing them, and I didn’t even know there was a tool! (apart from me!)

I’ve had that “life of pots” article bookmarked for about 20 years! I’ve referred to it many times over that time.
I can’t tell you how forums and threads I’ve seen it posted in! Good to see it still being used.

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